The instant invention relates to an electrophotocopying machine having a reciprocating carriage moved by an endless drive member, and more particularly to a clutching device for reversing the direction of the carriage output drive member without reversing the direction of the endless drive member.
Many electrophotocopying machines employ a reciprocating carriage to scan expose a document to be copied across an illuminating station that comprises an exposure slit located on the top of the cabinet housing, underneath the reciprocating carriage. During a copy cycle, the carriage moves in a given direction a predetermined distance that is usually long enough to enable the copier to make copies of fourteen inch long documents. Once the carriage has travelled the predetermined distance and the original document has been completely scanned, the carriage reverses its direction in order to return to its original starting or home position. Typically, an endless chain is powered by a motor and drives the carriage through its cycle, but complex and expensive multiple gearing and clutching mechanisms are required in order to reverse the direction of the carriage output drive member without reversing the direction of the chain input.